DDNS problems

I am having trouble with using ddns with my 3cx for android. When I use my dynamic ip
address (xx.xx.xx.xx) everything works perfectly. Changing it to my ddns
name (goldstar.xx.com) the android registers and receives calls, but does not make calls.
It just goes back to 'available' when I attempt to call out. I also do not see anything
in the 3cx log. Does this make any sense?

As I stated, it registers and receives call using the ddns name. So the ddns is resolving the ip address or it would not even register. The only it does not do is place calls, which it does just fine if the numbered ip address is used instead.